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Message-ID: <844e996e-09dd-7f1e-cc21-25be65137152@hisilicon.com>
Date: Thu, 10 Jul 2025 12:09:08 +0800
From: Junxian Huang <huangjunxian6@...ilicon.com>
To: Zhu Yanjun <yanjun.zhu@...ux.dev>, <saeedm@...dia.com>, <leon@...nel.org>,
<tariqt@...dia.com>, <andrew+netdev@...n.ch>, <davem@...emloft.net>,
<edumazet@...gle.com>, <kuba@...nel.org>, <netdev@...r.kernel.org>,
<linux-rdma@...r.kernel.org>
Subject: Re: [PATCH rdma-next 1/1] net/mlx5: Fix build -Wframe-larger-than
warnings
On 2025/7/10 11:49, Zhu Yanjun wrote:
> When building, the following warnings will appear.
> "
> pci_irq.c: In function ‘mlx5_ctrl_irq_request’:
> pci_irq.c:494:1: warning: the frame size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>
> pci_irq.c: In function ‘mlx5_irq_request_vector’:
> pci_irq.c:561:1: warning: the frame size of 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>
> eq.c: In function ‘comp_irq_request_sf’:
> eq.c:897:1: warning: the frame size of 1080 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>
> irq_affinity.c: In function ‘irq_pool_request_irq’:
> irq_affinity.c:74:1: warning: the frame size of 1048 bytes is larger than 1024 bytes [-Wframe-larger-than=]
> "
>
> These warnings indicate that the stack frame size exceeds 1024 bytes in
> these functions.
>
> To resolve this, instead of allocating large memory buffers on the stack,
> it is better to use kvzalloc to allocate memory dynamically on the heap.
> This approach reduces stack usage and eliminates these frame size warnings.
>
> Signed-off-by: Zhu Yanjun <yanjun.zhu@...ux.dev>
> ---
> 1. Only build tests;
> 2. It is not a bug fix. Thus no Fixes tag;
> ---
> drivers/net/ethernet/mellanox/mlx5/core/eq.c | 16 +++++---
> .../mellanox/mlx5/core/irq_affinity.c | 15 +++++--
> .../net/ethernet/mellanox/mlx5/core/pci_irq.c | 40 +++++++++++++------
> 3 files changed, 51 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eq.c b/drivers/net/ethernet/mellanox/mlx5/core/eq.c
> index dfb079e59d85..66ce61eee804 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/eq.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/eq.c
> @@ -873,20 +873,26 @@ static int comp_irq_request_sf(struct mlx5_core_dev *dev, u16 vecidx)
> {
> struct mlx5_irq_pool *pool = mlx5_irq_table_get_comp_irq_pool(dev);
> struct mlx5_eq_table *table = dev->priv.eq_table;
> - struct irq_affinity_desc af_desc = {};
> + struct irq_affinity_desc *af_desc;
> struct mlx5_irq *irq;
>
> + af_desc = kvzalloc(sizeof(*af_desc), GFP_KERNEL);
> + if (!af_desc)
> + return -ENOMEM;
> +
> /* In case SF irq pool does not exist, fallback to the PF irqs*/
> if (!mlx5_irq_pool_is_sf_pool(pool))
> return comp_irq_request_pci(dev, vecidx);
...
>
> - af_desc.is_managed = false;
> - cpumask_copy(&af_desc.mask, cpu_online_mask);
> - cpumask_andnot(&af_desc.mask, &af_desc.mask, &table->used_cpus);
> - irq = mlx5_irq_affinity_request(dev, pool, &af_desc);
> + af_desc->is_managed = false;
> + cpumask_copy(&af_desc->mask, cpu_online_mask);
> + cpumask_andnot(&af_desc->mask, &af_desc->mask, &table->used_cpus);
> + irq = mlx5_irq_affinity_request(dev, pool, af_desc);
> if (IS_ERR(irq))
> return PTR_ERR(irq);
...
>
> + kvfree(af_desc);
> +
> cpumask_or(&table->used_cpus, &table->used_cpus, mlx5_irq_get_affinity_mask(irq));
> mlx5_core_dbg(pool->dev, "IRQ %u mapped to cpu %*pbl, %u EQs on this irq\n",
> pci_irq_vector(dev->pdev, mlx5_irq_get_index(irq)),
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c b/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c
> index 2691d88cdee1..929f93853843 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/irq_affinity.c
> @@ -47,29 +47,38 @@ static int cpu_get_least_loaded(struct mlx5_irq_pool *pool,
> static struct mlx5_irq *
> irq_pool_request_irq(struct mlx5_irq_pool *pool, struct irq_affinity_desc *af_desc)
> {
> - struct irq_affinity_desc auto_desc = {};
> + struct irq_affinity_desc *auto_desc;
> struct mlx5_irq *irq;
> u32 irq_index;
> int err;
>
> + auto_desc = kvzalloc(sizeof(*auto_desc), GFP_KERNEL);
> + if (!auto_desc)
> + return ERR_PTR(-ENOMEM);
> +
> err = xa_alloc(&pool->irqs, &irq_index, NULL, pool->xa_num_irqs, GFP_KERNEL);
> if (err)
> return ERR_PTR(err);
You forgot to free the kvzalloc() memory in these error branches
Junxian
> +
> if (pool->irqs_per_cpu) {
> if (cpumask_weight(&af_desc->mask) > 1)
> /* if req_mask contain more then one CPU, set the least loadad CPU
> * of req_mask
> */
> cpumask_set_cpu(cpu_get_least_loaded(pool, &af_desc->mask),
> - &auto_desc.mask);
> + &auto_desc->mask);
> else
> cpu_get(pool, cpumask_first(&af_desc->mask));
> }
> +
> irq = mlx5_irq_alloc(pool, irq_index,
> - cpumask_empty(&auto_desc.mask) ? af_desc : &auto_desc,
> + cpumask_empty(&auto_desc->mask) ? af_desc : auto_desc,
> NULL);
> if (IS_ERR(irq))
> xa_erase(&pool->irqs, irq_index);
> +
> + kvfree(auto_desc);
> +
> return irq;
> }
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c b/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
> index 40024cfa3099..48aad94b0a5d 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/pci_irq.c
> @@ -470,26 +470,32 @@ void mlx5_ctrl_irq_release(struct mlx5_core_dev *dev, struct mlx5_irq *ctrl_irq)
> struct mlx5_irq *mlx5_ctrl_irq_request(struct mlx5_core_dev *dev)
> {
> struct mlx5_irq_pool *pool = ctrl_irq_pool_get(dev);
> - struct irq_affinity_desc af_desc;
> + struct irq_affinity_desc *af_desc;
> struct mlx5_irq *irq;
>
> - cpumask_copy(&af_desc.mask, cpu_online_mask);
> - af_desc.is_managed = false;
> + af_desc = kvzalloc(sizeof(*af_desc), GFP_KERNEL);
> + if (!af_desc)
> + return ERR_PTR(-ENOMEM);
> +
> + cpumask_copy(&af_desc->mask, cpu_online_mask);
> + af_desc->is_managed = false;
> if (!mlx5_irq_pool_is_sf_pool(pool)) {
> /* In case we are allocating a control IRQ from a pci device's pool.
> * This can happen also for a SF if the SFs pool is empty.
> */
> if (!pool->xa_num_irqs.max) {
> - cpumask_clear(&af_desc.mask);
> + cpumask_clear(&af_desc->mask);
> /* In case we only have a single IRQ for PF/VF */
> - cpumask_set_cpu(cpumask_first(cpu_online_mask), &af_desc.mask);
> + cpumask_set_cpu(cpumask_first(cpu_online_mask), &af_desc->mask);
> }
> /* Allocate the IRQ in index 0. The vector was already allocated */
> - irq = irq_pool_request_vector(pool, 0, &af_desc, NULL);
> + irq = irq_pool_request_vector(pool, 0, af_desc, NULL);
> } else {
> - irq = mlx5_irq_affinity_request(dev, pool, &af_desc);
> + irq = mlx5_irq_affinity_request(dev, pool, af_desc);
> }
>
> + kvfree(af_desc);
> +
> return irq;
> }
>
> @@ -548,16 +554,26 @@ struct mlx5_irq *mlx5_irq_request_vector(struct mlx5_core_dev *dev, u16 cpu,
> {
> struct mlx5_irq_table *table = mlx5_irq_table_get(dev);
> struct mlx5_irq_pool *pool = table->pcif_pool;
> - struct irq_affinity_desc af_desc;
> + struct irq_affinity_desc *af_desc;
> int offset = MLX5_IRQ_VEC_COMP_BASE;
> + struct mlx5_irq *irq;
> +
> + af_desc = kvzalloc(sizeof(*af_desc), GFP_KERNEL);
> + if (!af_desc)
> + return ERR_PTR(-ENOMEM);
>
> if (!pool->xa_num_irqs.max)
> offset = 0;
>
> - af_desc.is_managed = false;
> - cpumask_clear(&af_desc.mask);
> - cpumask_set_cpu(cpu, &af_desc.mask);
> - return mlx5_irq_request(dev, vecidx + offset, &af_desc, rmap);
> + af_desc->is_managed = false;
> + cpumask_clear(&af_desc->mask);
> + cpumask_set_cpu(cpu, &af_desc->mask);
> +
> + irq = mlx5_irq_request(dev, vecidx + offset, af_desc, rmap);
> +
> + kvfree(af_desc);
> +
> + return irq;
> }
>
> static struct mlx5_irq_pool *
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